Cost-Effectiveness of Pembrolizumab for Previously treated MSI-H/dMMR Solid Tumors in Canada
Author(s)
François-Xavier Houde, Pharm.D, MSc1, Cédric Joyal, MS1, Daniel Ladino, MSc2, Aris Skandamis, MSc3, Matthew Madin-Warburton, MSc3, Kate Young, MPH, PhD4, Grant McCarthy, MSc5;
1Merck Canada Inc., Kirkland, QC, Canada, 2Lumanity, Dublin, Ireland, 3Lumanity, London, United Kingdom, 4Merck & Co., Inc., Rahway, NJ, USA, 5MSD (UK) Ltd., London, United Kingdom
1Merck Canada Inc., Kirkland, QC, Canada, 2Lumanity, Dublin, Ireland, 3Lumanity, London, United Kingdom, 4Merck & Co., Inc., Rahway, NJ, USA, 5MSD (UK) Ltd., London, United Kingdom
OBJECTIVES: This study evaluated the cost-effectiveness of pembrolizumab as monotherapy for the treatment of patients with unresectable or metastatic microsatellite instability-high/mismatch repair deficient (MSI-H/dMMR) solid tumors who have progressed following prior treatment and have no satisfactory alternative treatments from the Canadian healthcare payer perspective.
METHODS: Methodology was aligned to Canada's Drug Agency (CDA-AMC) guidance for economic evaluation of tumor-agnostic products. A multi-tumor partitioned survival model was constructed comprising pre-progression, progressed disease, and death health states. Long-term effects on costs and clinical outcomes were explicitly modeled in tumor sites where patient-level data were deemed sufficient for economic modeling from KEYNOTE-164 and KEYNOTE-158 (colorectal, endometrial, gastric and small intestine). Comparator outcomes were informed by published sources, using MSI-H/dMMR patient data where possible. To comply with CDA-AMC guidance, no clinical benefits were assumed for pembrolizumab in the remaining tumor sites, but incremental acquisition costs were attributed. Each tumor was modeled independently; results were combined using a weighting of tumor site distribution from Canadian epidemiological data. The comparator reflects a weighted average of available treatment options in the Canadian landscape. Drug acquisition, administration, adverse event, monitoring, subsequent treatment, end-of-life, and testing costs were included.
RESULTS: Pembrolizumab, at list price, was associated with $223,263 in total costs, 5.95 life years (LYs), and 4.16 quality-adjusted life years (QALYs) when all tumor sites were included. Comparators were associated with $109,493 in total costs, 1.19 LYs, and 0.81 QALYs. This results in a deterministic incremental cost-effectiveness ratio (ICER) of $33,946 per QALY. Scenario analysis indicated that results were robust, and not sensitive to alternative extrapolation curve selections or treatment waning assumptions.
CONCLUSIONS: This study demonstrates that pembrolizumab provides a valuable and cost-effective therapy for Canadian patients with previously treated MSH-H/dMMR solid tumors, despite conservative assumptions where the absence of clinical benefits in some tumor sites is contrary to clinical expert expectations.
METHODS: Methodology was aligned to Canada's Drug Agency (CDA-AMC) guidance for economic evaluation of tumor-agnostic products. A multi-tumor partitioned survival model was constructed comprising pre-progression, progressed disease, and death health states. Long-term effects on costs and clinical outcomes were explicitly modeled in tumor sites where patient-level data were deemed sufficient for economic modeling from KEYNOTE-164 and KEYNOTE-158 (colorectal, endometrial, gastric and small intestine). Comparator outcomes were informed by published sources, using MSI-H/dMMR patient data where possible. To comply with CDA-AMC guidance, no clinical benefits were assumed for pembrolizumab in the remaining tumor sites, but incremental acquisition costs were attributed. Each tumor was modeled independently; results were combined using a weighting of tumor site distribution from Canadian epidemiological data. The comparator reflects a weighted average of available treatment options in the Canadian landscape. Drug acquisition, administration, adverse event, monitoring, subsequent treatment, end-of-life, and testing costs were included.
RESULTS: Pembrolizumab, at list price, was associated with $223,263 in total costs, 5.95 life years (LYs), and 4.16 quality-adjusted life years (QALYs) when all tumor sites were included. Comparators were associated with $109,493 in total costs, 1.19 LYs, and 0.81 QALYs. This results in a deterministic incremental cost-effectiveness ratio (ICER) of $33,946 per QALY. Scenario analysis indicated that results were robust, and not sensitive to alternative extrapolation curve selections or treatment waning assumptions.
CONCLUSIONS: This study demonstrates that pembrolizumab provides a valuable and cost-effective therapy for Canadian patients with previously treated MSH-H/dMMR solid tumors, despite conservative assumptions where the absence of clinical benefits in some tumor sites is contrary to clinical expert expectations.
Conference/Value in Health Info
2025-05, ISPOR 2025, Montréal, Quebec, CA
Value in Health, Volume 28, Issue S1
Code
EE350
Topic
Economic Evaluation
Disease
SDC: Oncology